Oral care products include a variety of chemical agents that perform a range of functions. For instance, toothpastes, mouthwashes and whiteners include chemical agents that help to clean teeth, kill bacteria, freshen breath and/or whiten teeth. These products typically cooperate with a device such as a toothbrush, an applicator device, or a tongue scraper, to perform their intended functions. In addition, chemical agents in these products may provide secondary benefits such as providing pleasing flavors or odors.
Many oral care products are configured to be multi-functional. For example, conventional toothpaste is configured to assist with multiple functions, such as cleaning teeth, fighting tartar, providing fluoride protection, freshening breath and whitening teeth. As such, the concentrations and types of chemical agents therein are limited by chemical interaction considerations and by chemical stability considerations thereof during prolonged storage.
Oral care products that are directed to whitening teeth include an oxidizing agent as the primary active ingredient, such as hydrogen peroxide. These products are formulated into liquids, pastes or gels for application to users' teeth. Upon storage, these products lose their whitening efficacy over time. In addition, these products have a brief period of efficacy when applied to the teeth in the oral cavity. For example, saliva contains high concentrations of the enzyme catalase, which on contact rapidly decomposes hydrogen peroxide into gaseous oxygen and water and so that there is only transitory contact of the peroxide whitening agent with the teeth. In addition, the low viscosities of aqueous peroxide solutions do not allow the peroxide whitening agent to remain in contact with the teeth for as long as is necessary to effect substantive whitening, because of the constant flushing effects of salivary secretions. As such, it is desirable to have high concentrations of oxidizing agents or effective oxidizing agents applied directly to teeth.
Toothbrushes are known that generate beneficial agents, including oxidizing agents when needed during brushing. U.S. Pat. No. 5,921,251 to Joshi discloses a toothbrush that generates beneficial oral care agents within the toothbrush when needed during brushing and that delivers them to the user's teeth once they are generated. The Joshi toothbrush generates within the toothbrush handle a fluid containing an oxidizing agent, which it delivers to the toothbrush bristles. The agent is generated via an electrochemical gas-generating cell within the toothbrush handle or via a photoelectrochemical cell within the handle.
The Joshi toothbrush does not generate its beneficial agents in situ at the application site, but instead generates them internally and subsequently transfers them to the application site. The Joshi toothbrush generates its beneficial agents from an electrolyte stored within the toothbrush handle (using its electrochemical gas generator), or it generates them from a catalyst stored within the handle via the application of light from an internal light source.
Toothbrushes are also known that generate ionized molecules by applying a voltage across electrodes on a toothbrush handle in contact with a dentifrice slurry. U.S. Pat. No. 6,496,998 to Moran; U.S. Patent Publication 2003/0054321 to Moran; and U.S. Patent Publication 2002/0177107 to Moran each discloses a toothbrush that generates weak acids of fluoride via the application of an electric charge to electrodes on the toothbrush handle in contact with an aqueous dentifrice containing sodium fluoride. The Moran toothbrushes generate fluoride ions by applying a three-volt electric charge to the aqueous slurry containing sodium fluoride. It also generates diatomic oxygen and hydrogen ions via the electrolysis of water in the slurry from same electric charge. The hydrogen ions combine with the fluoride ions to produce weak acids of fluoride (HF), which reduce the amount of acid-producing bacteria in plaque. The Moran references do not disclose a toothbrush that generates oxidizing agents other than oxygen itself via the application of an electric charge to an electrolyte. Further, the Moran references disclose generating oxygen and hydrogen ions along the toothbrush handle and do not disclose generating oxidizing agents in situ at the application site within a field of cleaning elements.